This invention relates to a method of manufacturing a low voltage ink jet printing module.
An ink jet printing module ejects ink from an orifice in the direction of a substrate. The ink can be ejected as a series of droplets generated by a piezoelectric ink jet printing module. An example of a particular printing module can have 256 jets in four groups of 64 jets each. A piezoelectric ink jet printing module can include a module body, a piezoelectric element, and electrical contacts that drive the piezoelectric element. Typically, the module body is a rectangular member into the surfaces of which are machined a series of ink chambers that serve as pumping chambers for the ink. The piezoelectric element can be disposed over the surface of the body to cover the pumping chambers in a manner to pressurize the ink in the pumping chambers to eject the ink.
In general, an ink jet printing module includes a stiffened piezoelectric element. The stiffened piezoelectric element improves jetting of ink when a low voltage is applied to the element compared to non-stiffened piezoelectric element. This can also allow ink jet modules to be smaller because the piezoelectric element has been strengthened. The stiffened piezoelectric element has a rigidity in at least one dimension that is higher than a flat piezoelectric element. The stiffened piezoelectric element can have a curved surface to strengthen the element. The module can jet ink when driven with a voltage of less than 60 volts.
In one aspect, a method of manufacturing an ink jet printing module includes injection molding a precursor into a mold to form a stiffened piezoelectric element, and positioning the piezoelectric element over an ink chamber to subject ink within the chamber to a jetting pressure upon applying a jetting voltage.
In another aspect, a method of depositing ink includes delivering ink to an ink chamber, and applying a jetting voltage across a first electrode and a second electrode on a face of a stiffened piezoelectric element to subject ink within the chamber to a jetting pressure, thereby depositing ink from an exit orifice of the ink chamber.
In another aspect, an ink jet printing module includes an ink chamber, a stiffened piezoelectric element having a region exposed to the ink chamber, and electrical contacts arranged on a surface of the piezoelectric element for activation of the piezoelectric element when a jetting voltage is applied to the electrical contacts. The piezoelectric element is positioned over the ink chamber to subject ink within the chamber to jetting pressure. The region of the stiffened piezoelectric element exposed to the ink chamber can have a curved surface.
The stiffened piezoelectric element can have a curved surface over the ink chamber. The curved surface can be concave relative to the ink chamber. The curved surface can have a substantially constant radius of curvature. The curved surface can be a spherical section or a cylindrical section. A wall of the chamber can be oriented to contact the stiffened piezoelectric element at an angle of greater than ninety degrees. The piezoelectric element can include lead zirconium titanate.
The ink jet printing module can include a series of chambers. Each of the chambers can be covered by a single piezoelectric element. A first electrode and a second electrode can be placed on a surface of the piezoelectric element.
Details are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.